He was unable to give an estimated overall toll for the disaster, telling a news conference at UN headquarters "it is estimated now over 10,000 people perished".
UN humanitarian chief Valerie Amos said in a statementthat"local officials estimate that some 10,000 people were killed in one city alone," referring to Tacloban, capital of the eastern province of Leyte.
The United Nations was to appeal for significant international aid for victims on Tuesday.
Relief cannot come soon enough for Joan Lumbre-Wilson, 54, who was among a large crowd of people gathered around one of the few relief centres in the ruined city of Tacloban.
"We want an organised, coordinated brigade to collect the dead bodies, bring food and stop the looting," she said.